Keeping a fork up to date on someone else's (non-enterprise) Gitlab

So this seems like a fairly basic problem. I have a project on a remote Gitlab instance (hosted on a server that I do not control and cannot ssh into to perform command-line operations - so anything I do within this server needs to happen through the Gitlab GUI). This project is a fork of another project hosted on this same remote Gitlab instance.

So… my question: when the owners of the original project make updates, how exactly are those updates supposed to end up in my fork? The universal answer to this seems to be “repository mirroring,” which sounds like a great solution… if your Gitlab is enterprise. This one is not.

What exactly are people working in non-enterprise versions of Gitlab supposed to do in this situation? Followup question: why does it seem like this (again, very basic) issue is not addressed anywhere? All discussions relating to keeping forks updated seem to begin and end with either repository mirroring or manually-entered git commands. I can’t be anywhere near the first person for whom neither of these options is available.